package com.aulac.crm.webapp.taglib;

import java.io.IOException;
import java.text.Collator;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Locale;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;

import org.displaytag.tags.el.ExpressionEvaluator;

import com.aulac.crm.model.LabelValue;

/**
 * Tag for creating multiple &lt;select&gt; options for displaying a list of
 * country names.
 * 
 * <p>
 * <b>NOTE</b> - This tag requires a Java2 (JDK 1.2 or later) platform.
 * </p>
 * 
 * @author Jens Fischer, Matt Raible
 * @version $Revision: 1.4.2.1 $ $Date: 2006-06-10 08:00:48 -0600 (Sat, 10 Jun
 *          2006) $
 */
public class CountryTag extends TagSupport {
	private static final long serialVersionUID = 3905528206810167095L;
	private String name;
	private String prompt;
	private String scope;
	private String selected;

	public void setName(String name) {
		this.name = name;
	}

	public void setPrompt(String prompt) {
		this.prompt = prompt;
	}

	public void setDefault(String selected) {
		this.selected = selected;
	}

	public void setToScope(String scope) {
		this.scope = scope;
	}

	/**
	 * Process the start of this tag.
	 * 
	 * @return int status
	 * @exception JspException
	 *                if a JSP exception has occurred
	 * @see javax.servlet.jsp.tagext.Tag#doStartTag()
	 */
	public int doStartTag() throws JspException {
		ExpressionEvaluator eval = new ExpressionEvaluator(this, pageContext);

		if (selected != null) {
			selected = eval.evalString("default", selected);
		}

		Locale userLocale = pageContext.getRequest().getLocale();
		List countries = this.buildCountryList(userLocale);

		if (scope != null) {
			if (scope.equals("page")) {
				pageContext.setAttribute(name, countries);
			} else if (scope.equals("request")) {
				pageContext.getRequest().setAttribute(name, countries);
			} else if (scope.equals("session")) {
				pageContext.getSession().setAttribute(name, countries);
			} else if (scope.equals("application")) {
				pageContext.getServletContext().setAttribute(name, countries);
			} else {
				throw new JspException(
						"Attribute 'scope' must be: page, request, session or application");
			}
		} else {
			StringBuffer sb = new StringBuffer();
			sb.append("<select name=\"").append(name).append("\" id=\"")
					.append(name).append("\" class=\"select\">\n");

			if (prompt != null) {
				sb.append("    <option value=\"\" selected=\"selected\">");
				sb.append(eval.evalString("prompt", prompt)).append(
						"</option>\n");
			}

			for (Object country1 : countries) {
				LabelValue country = (LabelValue) country1;
				sb.append("    <option value=\"").append(country.getValue())
						.append("\"");

				if ((selected != null) && selected.equals(country.getValue())) {
					sb.append(" selected=\"selected\"");
				}

				sb.append(">").append(country.getLabel()).append("</option>\n");
			}

			sb.append("</select>");

			try {
				pageContext.getOut().write(sb.toString());
			} catch (IOException io) {
				throw new JspException(io);
			}
		}

		return super.doStartTag();
	}

	// /**
	// * Release aquired resources to enable tag reusage.
	// *
	// * @see javax.servlet.jsp.tagext.Tag#release()
	// */
	// public void release() {
	// super.release();
	// }

	/**
	 * Build a List of LabelValues for all the available countries. Uses the two
	 * letter uppercase ISO name of the country as the value and the localized
	 * country name as the label.
	 * 
	 * @param locale
	 *            The Locale used to localize the country names.
	 * 
	 * @return List of LabelValues for all available countries.
	 */
	@SuppressWarnings("unchecked")
	protected List<LabelValue> buildCountryList(Locale locale) {
		final Locale[] available = Locale.getAvailableLocales();

		List<LabelValue> countries = new ArrayList<LabelValue>();

		for (Locale anAvailable : available) {
			final String iso = anAvailable.getCountry();
			final String name = anAvailable.getDisplayCountry(locale);

			if (!"".equals(iso) && !"".equals(name)) {
				LabelValue country = new LabelValue(name, iso);

				if (!countries.contains(country)) {
					countries.add(new LabelValue(name, iso));
				}
			}
		}

		Collections.sort(countries, new LabelValueComparator(locale));

		return countries;
	}

	/**
	 * Class to compare LabelValues using their labels with locale-sensitive
	 * behaviour.
	 */
	public class LabelValueComparator implements Comparator {
		private Comparator c;

		/**
		 * Creates a new LabelValueComparator object.
		 * 
		 * @param locale
		 *            The Locale used for localized String comparison.
		 */
		public LabelValueComparator(final Locale locale) {
			c = Collator.getInstance(locale);
		}

		/**
		 * Compares the localized labels of two LabelValues.
		 * 
		 * @param o1
		 *            The first LabelValue to compare.
		 * @param o2
		 *            The second LabelValue to compare.
		 * 
		 * @return The value returned by comparing the localized labels.
		 */
		@SuppressWarnings("unchecked")
		public final int compare(Object o1, Object o2) {
			LabelValue lhs = (LabelValue) o1;
			LabelValue rhs = (LabelValue) o2;

			return c.compare(lhs.getLabel(), rhs.getLabel());
		}
	}
}
